Lubricant



Patented Dec. 25, 1951 LUBRECANT Roland F. Bergstrom and Jacobus M. Plantfeber,

Martinez, Calif., assignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application March 8, 1947, Serial No. 733,424

13 Claims. (Cl. 252-334) This invention relates to lubricating compositions, which are especially suitable for use in heavy duty engines. More particularly, this invention pertains to lubricating compositions containing a combination of oil additives which produce, improved heavy duty lubricants, particularly suitable for truck, bus, tractor engines, as well as all types of diesel engines, and the like.

Hydrocarbon oils such as mineral lubricating oils and the like, as well as synthetic oils are generally unsuited for heavy duty lubrication due to the extreme pressures, heavy loads and high temperatures developed in above engines under operating conditions. Oils, when subjected to such conditions, rapidly deteriorate and break down, forming sludges, varnish and lacquer coatings, corrosive acidic materials which attack and damage alloyed metals, and other contaminants which cause wear, scratching, scufiing and scoring'of engine parts as well as ringsticking and seizure.

Other conditions which accentuate and accelerate deterioration of base lubriants and which account at least in part for their rapid oxidation is the presence of small amounts of moisture formed or present in the lubricant, or blowby vapors from fuels which enter the lubricating system and form harmfuldeterioration products and the like. Also the close tolerances to which engine parts are machined as. well as the restricted clearances between various engine parts ag ravate this situation and aid in breaking down the lubricant. This is due to the fact that varnish and/or lacquer coatings on various engine parts such as rings, valves, pistons and cylinder walls, caused by oil deterioration diminish side clearances, act as heat insulators, both conditions causing an increase in oil temperature resulting infurther breakdown. Lacquer formations are attributed to oxidation of oils and are hard resinous materials having a tendency to adhere on metal surfaces and form thereon a hard deposit which blisters, chips thereby acting as an abrasive capable of scratching surfaces and blocking oil passages.

Ring and piston sticking, clogging and fouling of an engine is'also caused by sludge resulting from oxidation of oils at high loads and elevated temperatures. Sludges are extremely harmful for in addition to causing wear and corrosion they coat and clog up the circulating System of engines thereby decreasing their efiiciency.

Oiloxidation and decomposition products are highly corrosive especially to alloys such as oopper-lead and cadmium-silver bearings and the like. Other factors can account for corrosion and they are complex in nature and varied in origin. For example, acids found or formed in oil or fuel may attack alloy bearings. high temperatures on modern bearings of. sulfur derived from certain of its compounds or even found free in the oil or fuel, may be very serious. Thus the presence of certain sulfur compounds may induce pitting of bearing surfaces, such as exhaust valve stem guides, etc. These conditions which are generally encountered in heavy duty lubrication of engines not only result in heavy damage but frequently in its complete failure.

Heavy duty lubricants often must have socalled extreme pressure properties so as to withstand wear and protect bearing surfaces under stringent conditions. It has been found, however, that such additives generally increase engine deposits and are highly corrosive. The problem of compounding a lubricant for heavy duty purposes, having satisfactory anti-oxidant, detergent, anti-wear, anti-corrosion and extreme pres sure properties has not been solved up to the present time to the best knowledge of applicants.

It is therefore an object of this invention to provide a heavy duty lubricating composition suitable for use in engines operating at extremely high temperatures and under heavy loads. It is another object of this invention to provide a noncorrosive lubricating composition suitable for heavy duty lubrication. These and other objects of this invention will be apparent from the following description and the appended claims.

Broadly stated, this invention comprises a lubricant containing minor amounts of substantially oil-soluble derivatives of open-chain organic compounds containing nitrogen, oxygen, and/ or sulfur and/or metal derivatives thereof and oil-soluble metal derivatives resulting from the condensation of phenolic and/or thiophenolic compounds with an aldehyde. If desired, lubricants thus compounded can be still further im proved by addition thereto of minor amounts of oil-soluble salts of organic sulfonic acids and/or aryl amines.

The open-chain organic compounds which contain the elements referred to above can be represented by the general formulas:

Again, the effect at ifand III being sulfur. Thev R radicals-may contain sulfonates. Compounds represented by these formulas are referred to as carbamates, monothiocarbamates, e. g. thiolcarbamates; and thionocarbamates, dithiocarbamates and thiuran sulfides and the like.

The salt derivatives of compounds as represented by Formula I may include the alkali and alkaline earth metals such as Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba as well as other metals such as Al, Cu, Zn, Cd, Va, Cr, Mo, Mn, Fe, Co, Ni and the like, and nitrogen bases such as ammonium, alkyl, aralkyl, aryl, cycloalkyl and heterocyclic amines. Salts of the carbamates which are particularly preferred are Ca, Ba, A1 and Zn.

Typical members of additives as represented by Formula I are the Zn, Al, Pb, Fe, Ca, Ba, Na

and amine salts of dibutyl mono and dithiocarethyl ester, dithiocarbamic phenyl ester, phenyl dithiocarbamic phenyl ester; tetra methyl thiuram sulfide, tetra methyl-thiuram disulfide, tetra ethyl thiura'm sulfide, dipentamethylene thiuram tetrasulfide, dibutyl-diethyl thiuram disulfide, tetrabutyl thiuram .disulfide, tetraisopropyl thiuram disulfide, tetrapropyl-thiuram disulfide, and the like. The amount of this type of additive which is added to a base oil is generally less than 1% by weight, although greater quantities may be used. The preferred range is between about 0.1% and up to by weight, depending upon the oil base, concentration of the other additive and conditions of use.

The other main additive component of this invention is a metal salt of a condensation product of a phenolic compound with an aldehyde.

Suitable phenolic compounds can be representedby the general formula (IV) XH wherein Ar is a mono or polynuclear aromatic ring compound, X can be oxygen or sulfur, Y is a polar radical such as chlorine, nitro or amine, R is a hydrocarbon having a plurality of carbon atoms and if desired having attached thereon polar groups, n is an integer of at least 1, and m can be zero or an integer of less than 2. Compounds illustrative of Formula IV and which may be used to form the condensation reaction are dibutyl phenol and its thiophenol, amyl phenol and its thiophenol, tertiary butyl phenol and its thiophenol, p-tertiary amyl phenol and its thiophenol, octyl phenol and its thiophenol, p-isooctyl phenol, iso butyl phenol, nonyl' phenol and their thiophenyls, cetyl phenol and its thiophenol, alkyl amino phenol, alkyl aminonaphthol andthe like.

Aldehydes which can be used to form condensation products with the above phenolic com- 4 pounds can be aliphatic, aromatic or cyclic aldehydes. Specifically formaldehyde, acetaldehyde, crotonaldehyde, butyraldehyde; benzaldehyde; furaldehyde and the like can be used.

The condensation product is formed at rather elevated temperatures using an acid or basic catalyst. The salts of said condensation products may be alkali, alkaline earth or heavy metal, e. g. Na, K, Li, Ca, Ba, B, Mg, A1, Zn, Cu, Pb, Fe, Ni, Co, Mn, Cr, Sn and the like.

The salts of the condensation product of an alkyl phenolic compound and an aldehyde may be prepared by first condensing at an elevated temperature, for example, an octyl phenol with formaldehyde in the presence of a suitable sol vent and catalyst. The condensation product is then removed and dispersed in a hydrocarbon oil to which is added the metal forming constituent such as hydrated lime and the mass is agitated at an elevated temperature until the calcium salt of said condensation reaction forms. The salt formed can be purified by solvent treatment and filtration.

Instead of forming the salt in a two step process it can be formed in one step by simply admixing in a suitable solvent an alkyl phenol, an aldehyde'and for example hydrated lime and reacting the mixture at an elevated temperature under agitation until the calcium salt of the alkyl phenol-aldehyde condensation reaction forms. The product is recovered and purified by conventional means.

Typical members of this type of additive are the Ca, Ba, Sr, Na, K, Li, Al, Zn, etc. salts of the condensation reaction between:

Octyl phenol-formaldehyde Octyl phenol-acetaldehyde Isooctyl phenol-acetaldehyde Isooctyl phenol-crotonaldehyde Octyl phenol-benzaldehyde Octyl phenol-furaldehyde Octyl thiophenol-formaldehyde Octyl thiophenol-furaldehyde Amyl phenol-furaldehyde- Amyl phenol-formaldehyde Some of the salts of condensation reaction between a phenolic compound and an adehyde are difficulty soluble in oil. However, these may be solubilized therein for example by the procedure described by Cornell in U. S. Patent 2,042,880. A simpler method which is effective for many of these salts is to dissolve them in a suitable solvent such as benzene, and then, while adding oil, gradually remove the benzene by distillation, for example, by passing an inert gas (nitrogen, natural gas, etc.) through the mixture at an elevated temperature. This generally results in a stable concentrate of the salt in the oil which may be then diluted with more oil to the desired salt concentration. On the other hand, the salt may often be incorporated in an oil, without preparing an intermediate concentrate, by simply adding the desired concentrate of the salt to the oil at an elevated temperature with agitation. The amount of this additive need not be used above about 2% by weight although amounts as high as 5 to 25% can be used. The preferred range is between about 0.05% to 6%. A general practical range is between about 0.2% and about 4% by wt.

Lubricants containing the above discussed additives result in excellent heavy duty compositions, the lubricating properties of which can be enhanced by addition thereto of an oil-soluble 'salt of an organic sulfonic acid and/or an aryl amine.

The general class of aryl amines are the oilsoluble, relatively stable, aromatic amine, free from corrosive sulfur, preferably having at least two aromatic rings, which may be condensed in one radical attached, to the nitrogen atom. Especially valuable are those amines which contain at least one aromatic nucleus having two or more condensed or polycyclic aromatic rings. Thus, preferred compounds are, for example, the naphthylamines: primary, secondary or tertiary alkyl, aryl or aralkyl amines in which the alkyl, aryl or aralkyl radicals are attached to an aromatic nucleus or preferably to the nitrogen atom or both, such as phenyl-alpha or beta-naphthylamine, tetraline naphthylamine, alpha alpha, alpha beta, or beta beta dinaphthylamines, various phenanthryl, anthryl or picyl naphthylamines, xenyl naphthylamines, benzyl phenyl naphthylamines, diphenyl naphthylamines, pheny xenyl naphthylamines, dixenyl naphthylamines; also various phenanthryl, anthryl or picyl phenyl amines, etc. The N-aryl substituted naphthylamines are in general, more useful for our purpose.

If desired however, other aryl amines may be used, such as cliamino diaryl alkanes, e. g., di-

amino diphenyl methane, tetramethyl diamino diphenyl methane, tetramethyl diamino triphenyl methane, tetra ethyl diamino triphenyl methane, diamino diphenyl ethane, diamino ditolyl ethane, etc., alkylated diaryl amines, e. g.

p-ethyl diphenylamine, rn-ethyl diphenylamine, p-isopropyl diphenylamine, monoand polyamyl, hexyl, heptyl, octyl, nonyl, decyl, hexadecyl, cyclohexyl, methyl cyclohexyl and other alkyl substituted diphenylamines, etc.

The aryl amines may, in some cases, contain one or more substituents, such as hydroxyl, chloro, alkoxy, hydroxyalkyl, amino, n-alkylated amino,

n-alkylated amino alkylene, etc radicals. As illustrative of these substituted aryl amines. the following may be mentioned: p-methoxy p'-isopropyl diphenyl amine, and 1,8-diamino naphthalene,

The amount of aryl amine when used as an additive may vary from less than 1% up to 10% by weight, the preferred range being between about 0.05 and 2% by weight.

The other additive which may be added with compositions of this invention are salts of organic sulfonic acids, preferably petroleum sulfonic acids.

Petroleum sulfonic acids which may be used advantageously to produce the metal sulfonates of this invention are preferably of the oil-soluble type which are obtained, for example, in the treatment of relatively heavy mineral oils, with concentrated sulfuric acid. In this kindof treatment, two types of sulfonic acids are produced the so-called green acids which are substantially oil-insoluble, and mahogany acids which are oilsoluble. It is the mahogany acids which we prefer to use for our purpose, although green acids may also yield certa n oil-soluble salts which are applicable for our purpose. These acids constitute complicated mixtures of many difi'erent hydrocarbon sulfonic acids, many of which are believed to be of aromatic character, although others are probably of naphthenic and aliphatic origin. Some of them produce better anti-ringsticking salts than others. In order to isolate the most efiective components, the oil-soluble acids or their salts may be subjected to a fractionation by countercurrent extraction with two mutually immis ib e solvents. a. hydrocarbon liquid such f be overestimated, because in certain types of as toluene, benzene, xylene, naphtha, kerosene, etc., and a water-soluble organic solvent such as a lower alcohol, glycol, glycerine, the latter pref erably containing some water. The active component of the mahogany acid i concentrated in the hydrocarbon solvent. This method of sepa ration has been describedby Retailliau in U. S. Patent 2,158,680.

If desired, lubricating oils containing the sulfonic acid salts may also be produced by heavy acid treatment withconcentrated or fuming sulfuric acid of a suitable lubricating oil, separating precipitated and suspended sludge, and neutralizing the dissolved sulfonic acid with lime or other oxide or hydroxide of a suitable polyvalent metal. The preferred salts are the basic salts of petroleum sulfonic acids.

. Other oil-soluble organic sulfonic acids suitable for our purpose may be produced by sulfonating alkyl aromatic hydrocarbons, such as alky-l benzenes, alkyl naphthalenes, alkyl anthramay produce an aromatic hydrocarbon suitable for the production of highly eiiicient sulfonic acids by condensing chlorinated paraflin wax, alkyl chlorides such as octyl, decyl, cetyl, etc., chlorides, fatty alcohols, long. chain olefins such as may be obtained in the cracking of wax, etc., with the aromatic hydrocarbons by means of suitable condensing agents such as Friedel- Crafts catalysts, sulfuric acid, P205, phosphoric acid, etc.

The organic sulfonic acids may, if desired, contain substitution radicals such ,as hydroxyl, primary, secondary or tertiary amine, ether, su1-- fide, hydrosulfide, disulfide, halogen, etc., radicals which may be attached to the ring or to side chains or both. For example, excellent for the present purpose are paraflin wax substituted naphthalene mono sulfonic acids which contain a sulfonic radical attached to one ring of the naphthalene nucleus and a hydroxyl or. amino radical attached. to the other ring. H

The sulfonates can be madesoluble in any type of mineral lubricating oil ranging from the lowest to the highest V. I. This is in marked contrast to many of the commercial anti-ringsticking salts of carboxylic acids which are soluble only in low V. I. oils, The importance of being able to produce both high V. I. and low V. 1. oils having good anti-ringsticking properties cannot diesel engines, low V. I. oils simply will not stand up, while in other types of diesel engines, low V. I. oils give as goodor better results than the oils of higher V. I.

Salts suitable for our use in composition of this invention must be free of free acid, and may be normal and preferably basic. If necessary, the sulfonic acids may be subjected to a hydrolyzing treatment before use in the compounded oil, to eliminate sulfate or other contaminants which may be present. If desired, salts of two or more of metals may be employed.

The amount ofsulfonatewhenused asan ad ditive may vary from less than 1% up to about 25% by weight, the preferred range being between about 0.05% and 10% by weight.

Basic oils may be selected from a wide variety" of natural oils such as paramnic, naphthenic and mixed base oils having a wide viscosity range. In addition synthetic oils may be used Orygen absorption test and thrust bearing corrosion test [Base oil 000 SUS at 100 F. motor stocin] Ca salt of the Conden- Tests in Thrust Bcar- 9? of sation Product of Zn salt of dibutyl 2 5 3 fi g ing Corrosion Mag g zg octyl phenol and dithiocarbamate, g g g gg g chine, Estimated per cent w, ggngldehyde, per per cent wt. cent wt (hours) g gimhgal (Corrosion,

0 0 0 0 1. 3 (I) 0. 9 G 0 0 1. 3 IOU-120 0. 9 0 0 0. 2 20. 6 155+ O 1. 0 0 23. 4 150+ 1. 2 1. 0 O 23. 4 150+ l. 2 1. 0 0. 4 0. 2 28. 7 155+ 1 Impossible to complete test because of excessive lacquerlng.

invention passed the CRC Tests L1, L2, L3, L4:

and L5. For purpose of illustration the following test results of oil compositions of invention are listed when subjected to a CRC Test L-4545 which is a 36 hour test in a Chevrolet engine using the following conditions:

Other additives can be added to the compositions of this invention in order to improve their performance. Thus E. P. additives such as sulfurized, sulfur-halogenated, and phosphor-suliurized organic compounds can be used; also oiliness agents, e. g. oleic or stearic acid, pour point depressors, anti-foaming agents, e. g. organic silicons, fiuoro organic compounds, nitro paraffins and the like.

Many modifications and variations of this invention as hereinbefore set forth can be made without departin from the spirit and scope thereof and only such limitation should be imposed as indicated in the appended claims.

We claim as our invention:

1. A lubricant comprising a major amount of a .lubricating oil and the combination of minor amounts, sufficient to prevent deterioration of said .oil, of from 0.05% to 6% of an oil soluble Minimum Maximum Average calcium salt of a condensation product of an alkyl phenol with formaldehyde and from 0.1% to EnginespcSdbRHPP 3,13 8 3,123 5 3,1 5% of zinc dibutyl dithiocarbamate, and minor ngine 0a ontempinsumplw 277 284 amounts of from 0.05% to 10% of a hydrocar- ?ilirtessigel s It.t 13.5 14- bon aromatic amine and of from 0.05% to 10% *Efifffjflff if: 197 203 199 of an oil-soluble metal salt of a petroleum sulitxth us t pressure, in liar-m g; 3g fonic acid.

a e r ,in 1 g gg ggg; secoids I 2. A heavy duty lubricant comprising a major p 300 cc 729 amount of a lubricating oil and the combination of minor amounts, suflicient to prevent de- The following table shows the composition of terioration of said oil, of from 0.05% to 6% of the lubricants run for comparative purposes, toan oil soluble calcium salt of a condensation gether with the average bearing weight loss 00- 55 product of an alkyl phenol with formaldehyde casioned by the use of the respective lubricants: and from 0.1% to 5% of zinc dihexyldithio- Table [Base oil 600 sus a 1!. motor stock] Ca salt of the Ca Salt of Zn salt of Phenyl a Bearing Petroleum f afigz s g g i dibutyl naphthylwt. loss Piston Sulionate Ph no! M1321 dithiocarbamamine per mg. per Lacquer Per Cent by fongaxdehyde ate per cent Wt. bearing Rating wt. per cent wt cent Wt.

0 0 o 0 805 2% 1.8 0 o 0 1.489 0 0 0 0.4 242 1 0 1.0 0 0.4 174 1 1.2 1.0 0 0 100 10 0.6 1.0 0 0.2 186 .10 2.7 0 1.0 0 07 10 1.2 1.0 0.4 0 a9 10 1.2 1.0 0.4 0.2 30 10 9h0urs.

Compositions of this invention were also sub jected toDxygen Absorption Test and a modified carbamate and of from 0.05% to 10% of a hydrocarbon aromatic amine and of from 0.05% to 9 10% of an oil-soluble metal salt of a petroleum sul onic acid.

3. A heavy duty lubricant comprising a major amount of a lubricating oil and the combination of minor amounts, suificient to prevent deterioration of said oil, of from 0.05% to 6% of an oil soluble calcium salt of a condensation product of an alkyl phenol with formaldehyde and from 0.1% to of calcium dibutyl dithiocarbamate and a minor amount of from 0.05% to of a hydrocarbon aromatic amine and of from 0.05% to 10% of an oil-soluble metal salt of a petroleum sulfonic acid.

4. A heavy duty lubricant comprising a major amount of a lubricating oil and the combination of minor amounts, sufficient to prevent deterioration of said oil, of from 0.05% to 6% of an oil .soluble calcium salt of a condensation product of an alkyl phenol with formaldehyde and from 0.1% to 5-% of zinc dibutyl dithiocarbamate and a minor amount of from 0.05% to 10% of an oil-soluble metal salt of a petroleum sulfonic acid.

5. A heavy duty lubricant comprising a maior amount of a lubricating oil and the combination of minor amounts, sufficient to prevent deterioration of said oil, of from 0.05% to 6% of an oil soluble calcium salt of a condensation product of an alkyl phenol with formaldehyde and from 0.1% to 5% of zinc dihexyldithiocarbamate and a minor amount of from 0.05% to 10% of an oil-soluble metal salt of a petroleum sulfonic acid.

6. A heavy duty lubricant comprisin a major amount of a lubricating oil and the combination of minor amounts, suflicient to prevent deterioration of said. oil, of from 0.05% to 6% of an oil soluble calcium salt of condensation product of an alkyl phenol with formaldehyde and from 0.1% to 5% of calcium dibutyl dithiocarbamate and a minor amount of from 0.05% to 10% of a hydrocarbon aromatic amine.

7. A heavy duty lubricant comprising a major amount of a lubricating oil and the combination of minor amounts, suflicient to prevent deterioration of said oil, of from 0.05% to 6% of an oil soluble metal salt of condensation product of an alkyl phenol with an aldehyde and from 0.1% to 5% of an oil soluble metal salt of dithiocarbamic acid.

8. A heavy-duty lubricant having the following formula:

Percent weight Ca salt of octyl phenol-formaldehyde condensation product 1 Zn dibutyldithiocarbamate 0.4 Ca petroleum sulfonate (oil-soluble) l Phenyl alpha-naphthylamine 0.2

Mineral lubricating oil g Balance 10 9. A heavy-duty lubricant having the following formula:

Percent Weight Ca salt of octyl phenol-formaldehyde condensation product 1 Zn dihexyldithiocarbamate 0.4 Ca petroleum sulfonate (oil soluble) 1 Phenyl alpha-naphthylamine 0.2 Mineral lubricating oil Balance 10. A heavy-duty lubricant having the following formula:

Percent weight Ca salt of octyl phenol-formaldehyde condensation product 1 Zn dialkyl dithiocarbamate (oil-soluble) 0.4 Ca petroleum sulfonate (oil-soluble) l Phenyl alpha-naphthylamine 0.2

and the balance consisting essentially of mineral lubricating oil.

11. A heavy-duty lubricant having the following formula:

Percent weight Ca salt of octyl phenol-formaldehyde condensation product 0.05-6 Zn dibutyl dithiocarbamate 0.1-5 Ca petroleum sulfonate (oil-soluble) 0.05-10 Phenyl alpha-naphthylamine 0.05-10 Mineral lubricating oil Balance 12. A heavy-duty lubricant having the following formula:

Percent Weight Ca salt of octyl phenol-formaldehyde condensation product -1 0.05-6 Zn dihexyl dithiocarbamate 0.1-5 Ca petroleum sulfonate (oil-soluble) 0.05-10 Phenyl alpha-naphthylamine 0.05-10 Mineral lubricating oil Balance 13. A heavy-duty lubricant having the following formula:

' Percent weight Ca salt of octyl phenol-formaldehyde condensation product 0.05-6 Zn dialkyl dithiocarbamate (oil-soluble) 0.1-5 Ca petroleum sulfonate (oil-soluble) 0.05-10 Phenyl alpha-naphthylamine 0.05-10 and the balance consisting essentially of mineral lubricating oil.

ROLAND F. BERGSTROM. JACOBUS M. PLANTFEBER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,280,419 Wilson Apr. 21, 1942 2,406,564 Rogers Aug. 27, 1946 2,410,652 Griffins et al Nov. 5, 1946 2,412,903 Miller et a1. Dec. 17, 1946 

13. A HEAVY-DUTY LUBRICANT HAVING THE FOLLOWING FORMULA: PERCENT WEIGHT CA SALT OF OCTYL PHENOL-FORMALDEHYDE CONDENSATION PRODUCT 0.05-6 ZN DIALKYL DITHIOCARBAMATE (OIL-SOLUBLE)- 0.1-5 CA PETROLUEM SULFONATE (OIL-SOLUBLE) 0.05-10 PHENYL ALPHA-NAPHTHYLAMINE 0.05-10 AND THE BALANCE CONSISTING ESSENTIALLY OF MINERAL LUBRICATING OIL. 